Spatio-temporal trends of mortality in small areas of Southern Spain

Abstract

Background: Most mortality atlases show static maps from count data aggregated over time. This procedure has several methodological problems and serious limitations for decision making in Public Health. The evaluation of health outcomes, including mortality, should be approached from a dynamic time perspective that is specific for each gender and age group. At the moment, researches in Spain do not provide a dynamic image of the population's mortality status from a spatio-temporal point of view. The aim of this paper is to describe the spatial distribution of mortality from all causes in small areas of Andalusia (Southern Spain) and evolution over time from 1981 to 2006.

Methods: A small-area ecological study was devised using the municipality as the unit for analysis. Two spatio-temporal hierarchical Bayesian models were estimated for each age group and gender. One of these was used to estimate the specific mortality rate, together with its time trends, and the other to estimate the specific rate ratio for each municipality compared with Spain as a whole.

Results: More than 97% of the municipalities showed a diminishing or flat mortality trend in all gender and age groups. In 2006, over 95% of municipalities showed male and female mortality specific rates similar or significantly lower than Spanish rates for all age groups below 65. Systematically, municipalities in Western Andalusia showed significant male and female mortality excess from 1981 to 2006 only in age groups over 65.

Conclusions: The study shows a dynamic geographical distribution of mortality, with a different pattern for each year, gender and age group. This information will contribute towards a reflection on the past, present and future of mortality in Andalusia.

Figure 1

Mortality from all causes trend, 1981-2006.

Figure 2

Mortality from all causes smoothed specific rate, 2006.

Figure 3

Probability that male mortality rate ratio is above 1 (under 45 age groups).

Figure 5

Probability that male mortality rate ratio is above 1 (over 45 age groups).

Figure 4

Probability that female mortality rate ratio is above 1 (under 45 age groups).

Figure 6

Probability that female mortality rate ratio is above 1 (over 45 age groups).